The ATM gene, mutated in ataxia-telangiectasia (A-T), was identified by positional cloning. The discovery of the ATM gene now allows the identification of A-T heterozygotes [Telatar et al., 1998], who may be at increased risk of cancer. The purpose of this study was to (a) identify sib's interest in carrier testing, (b) explore perception of carrier status, and (c) assess levels of understanding of genetics of A-T. This is the sib component of a study of 103 parents and sibs (68 parents and 35 sibs) of individuals with A-T. Thirty-five sibs from 24 families, including 26 adults and 9 adolescents, drawn from the University of California, Los Angeles, the A-T Clinical Center at the Johns Hopkins University School of Medicine, and the A-T Children's Project, were interviewed. Eighty-five percent of adult sibs stated correctly that if a child has A-T, both parents are heterozygotes; 76% knew the A-T gene had been identified. Ninety-two percent would request carrier testing for themselves if available. Seventy-nine percent would want their child tested for carrier status prior to the age of 18. Seventy-three percent believed that being a carrier is associated with increased health risks. Sibs have numerous misconceptions surrounding carrier status and genetics of A-T. Provision of factual information about genetic transmission is necessary, but unfortunately insufficient, to counter deeply held views of self and others. Genetic counseling, which explores the way in which this information is filtered and interpreted, could be an effective tool in dispelling family myths. We conclude that A-T sibs need comprehensive support in relation to carrier testing.
Copyright 1999 Wiley-Liss, Inc.